Karl Anderson made his New Japan debut on March 23rd, 2008 in the New Japan Cup. In the first round he lost to Koji Kanemoto, but during the tour he impressed New Japan enough that he was welcomed back. On March 29th he had a match against Manabu Nakanishi, but lost in under 10 minutes. Anderson did well in the mid-card for the rest of 2008, but he did not have any big wins over the elite of New Japan as he was sometimes lost in the shuffle in a large faction (GBH). Anderson did not participate in the G1 Climax or the G1 Tag League.

Anderson wrestled in New Japan for all of 2009, mostly teaming with fellow gaijin Giant Bernard. Anderson participated in the New Japan Cup, but he lost in the first round to Hirooki Goto.
Teaming with Giant Bernard, in May they defeated TenKoji to win a shot at the IWGP Heavyweight Tag Team Championship. They faced off against Team 3D for the titles on June 20th, but the CHAOS duo would come up short. Anderson did not participate in the G1 Climax, but in the G1 Tag League he teamed with his friend Giant Bernard, and the team defeated Apollo55 in the Finals to win the tournament. This gave them another title shot at the 2010 Tokyo Dome event.